Motor Torque Detection via Current Correction
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately determining the state of rotating bodies driven by motors without using torque sensors, leading to errors due to temperature-dependent torque measurements and inability to maintain constant temperature.
Innovation Solution
An image forming apparatus that measures motor current and corrects for temperature-induced changes using a current measurer and corrector, allowing for accurate torque acquisition and state determination without a torque sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a torque sensor is used to measure motor torque, then measurement accuracy is improved, but device complexity and cost increase due to additional components and space requirements
Solution Approach 1:
The patent replaces the mechanical torque sensor with an electrical measurement system. Motor torque is calculated by measuring the motor current and applying correction based on temperature characteristics, substituting the physical torque sensor with an electrical measurement and calculation approach that eliminates the need for additional mechanical components.
Solution Approach 2:
The patent introduces motor current as an intermediary measurement parameter. Instead of directly measuring torque, the system measures the motor current which is related to torque through the motor's electrical characteristics, and uses this current measurement as a mediator to infer torque while avoiding the need for a torque sensor.
2Device complexity
If motor current is measured to determine torque without temperature correction, then device complexity is reduced, but measurement precision deteriorates due to temperature-dependent torque variations
Solution Approach 1:
The patent implements a feedback mechanism where the measured motor current is corrected based on temperature characteristics. The system continuously monitors current and adjusts the torque calculation by applying correction factors derived from temperature-dependent motor characteristics, ensuring accurate torque measurement while maintaining system simplicity.
Solution Approach 2:
The patent compensates for temperature effects by changing the measurement parameters. Instead of directly using the raw current measurement, the system applies correction based on temperature characteristics, effectively adjusting the measurement parameter to account for temperature-induced variations in motor torque.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate determination of the state of rotating bodies, reducing errors caused by temperature changes and maintaining consistent operation without the need for torque sensors, thus enhancing the apparatus's reliability and efficiency.
Implementation Method 1
measuring a motor current flowing through a current supply path including a winding of the motor at a measurement timing that is a timing after the motor is started
Implementation Method 2
performs correction to cancel a current change amount based on a characteristic change depending on a temperature state of the motor at the measurement timing
Data Source
AI summary
An image forming apparatus that forms an image on a sheet includes: a rotating body that forms the image; a motor that rotationally drives the rotating body; a current measurer that measures a motor current flowing through a current supply path including a winding of the motor at a measurement timing that is a timing after the motor is started; a torque acquisitor that acquires a torque value of the motor, based on a measured value of the motor current; and a corrector that performs correction to cancel a current change amount based on a characteristic change depending on a temperature state of the motor at the measurement timing, in acquisition of the torque value by the torque acquisitor.